Returns Object's CNAME URL (without s3.amazonaws.com suffix)
using protocol specified in Service, e.g.
http://domain.com/key/with/path.extension. (you have to set the
CNAME in your DNS before using the CNAME URL schema).

Retrieves the object from the server. Method is used to download object
information only (content type, size). Notice: It does NOT download the
content of the object (use the #content method to do it). Notice: this do
not fetch acl information, use #request_acl method for that.